Thanks!

Like any weight distribution hitch, you want it to put enough tension on it to transfer weight from the tow vehicle's rear axle to the front axle. One of the best ways is to start on a level surface (if possible). While the tow vehicle is unhitched, take a measurement at the front and rear axles of the distance from the ground to the fender well. That is your starting distance.

Hitch the trailer, but do not attach or tighten the chains yet. Once that is done and the jack is raised, take a second measurement at the front and rear axles of your tow vehicle. Note the difference in measurements. then use the jack to remove lift the trailer so that there is very little if any weight on the ball.

Third, attach the plate and chains. Tighten the chains so that the sag in the rear is removed and the measurement in the front is close to what it was before you hitched the trailer. If you look at the pictures on page 9 of your manual, you will see what this should look like.

https://static1.squarespace.com/static/59717c92e6f2e15e9222f72c/t/59babe5ff14aa1f86f691391/1505410661027/WD+Manual+11-2013+low-res.pdf - https://static1.squarespace.com/static/59717c92e6f2e15e9222f72c/t/59babe5ff14aa1f86f691391/1505410661027/WD+Manual+11-2013+low-res.pdf

I have not owned an Andersen hitch. The same principle applies to all WDH's. You don't want to remove too much weight from the tow vehcle's rear axle.